Toxoplasma gondii: Role of the phosphatidylcholine-specific phospholipase C during cell invasion and intracellular development

The effect of D609, a specific inhibitor of phosphatidylcholine-specific ph ospholipase C, was investigated on cyst development of the Prugniaud strain of Toxoplasma gondii in vitro. Following treatment with the inhibitor 24 h after cell infection, cyst development was affected as assessed by stainin g with the bradyzoite-specific mAb CC2: the CC2-reactive antigen was shown to be differently located (in the wall versus the matrix under control cond itions). This correlated with a decrease in parasite multiplication induced by D609. Pretreatment of the parasites with D609 inhibited their entry int o the host cells, whereas pretreatment of the host cells enhanced the intra cellular multiplication of the parasites, without any effect on cell invasi on or cyst formation. Our results suggest a crucial role for phosphatidylch oline-specific phospholipase C in the pathophysiology of toxoplasmosis. (C) 1999 Academic Press.